Child-resistant closures

ABSTRACT

Closures for receptacles containing substances which are, or may be biologically harmful. Specifically the closures are characterized by features calculated to baffle a child who may attempt to remove the same. In general, the various embodiments disclosed include an inner male part or plug frictionally engaged in the receptacle exit for removal by an axially-applied force. An outer rotatable part or overcap is threadedly or otherwise detachably engaged with the receptacle. The overcap and plug are respectively provided with a male member having a left-hand thread and a cooperative female member having an internal, mating, left-hand thread. The overcap has a flexible top to which the male member is secured. To open the closure the top is depressed to engage the male and female left-hand threads, while the outer part is rotated. As such rotation is continued the plug is withdrawn substantially simultaneously with detachment of the overcap from the receptacle neck. The contents may then be discharged. Closure of the receptacle is the reverse of the foregoing. In the case of a threaded neck the rotary motion is continued to detach the overcap from the receptacle. In another form the overcap is inwardly flanged to engage a mating flange on the receptacle so that, upon engagement of the left-hand threaded members, both the plug and overcap may be detached by a simple pull.

United states'Patem [72] Inventor Sidney M. Libit 441 Lakeside Terrace, Glencoe, 111. 60022 [21 Appl. No. 832,587

22 Filed June 12, 1969 [45] Patented Jan. 19,1971

[54} CHILD-RESISTANT CLOSURES 12 Claims, 13 Drawing Figs.

Primary Examiner-George T. Hall Attorney-Leonard S. Knox ABSTRACT: Closures for receptacles containing substances which are, or may be biologically harmful. Specifically the closures are characterized by features calculated to baffle a child who may attempt to remove the same. In general, the various embodiments disclosed include an inner male part or plug frictionally engaged in the receptacle exit for removal by an axially-applied force. An outer rotatable part or overcap is threadedly or otherwise detachably engaged with the receptacle. The overcap and plug are respectively provided with a male member having a left-hand thread and a cooperative female member having an internal, mating, left-hand thread. The overcap has a flexible top to which the male member is secured. To open the closure the top is depressed to engage the male and female left-hand threads, while the outer part is rotated. As such rotation is continued the plug is withdrawn substantially simultaneously with detachment of the overcap from the receptacle neck. The contents may then be discharged. Closure of the receptacle isthe reverse of the foregoing. 1n the case of a threaded neck the rotary motion is continued to detach the overcap from the receptacle. In another form the overcap is inwardly flanged to engage a mating flange on the receptacle so that, upon engagement of the left-hand threaded members, both the plug and overcap may be detached by a simple pull.

PATENTEUJANIQIQYI 3,556,332

sum 2 0F 2 eme IIII CHILD-RESISTANT CLOSURES BACKGROUND OF THE INVENTION It has become increasingly evident that the opening of such receptaclesby children of tender age must be rendered impossible, or as nearly so as mechanical ingenuity can devise but without the use of a separateimplement which may be misplaced, a combination lock typeof mechanism or other means which will discourage widespread adoption because requiring a multiplicity of steps with which the average adult refuses to be bothered. However it has been found that devices requiring a substantial force applied axially of the closure combined with rotational force applied thereto concurrently or subsequently, provides an acceptable child-proof closure, but devices having this mode of operation presently known comprise three or more parts and, therefore, have not been readily accepted by the industry because of the'disproportionate cost.

The present invention operates on what may be termed the push-turn" principle but utilizes only two parts, thus enabling the closure to be sold at a much lower price than those heretofore proposed or used.

Another object is to provide a two'part closure characterized as aforesaid, the two parts of which may be fabricated from a plastic composition by a direct pull from the mold, i.e. side pulls or movable cores are not required. facturing cost is substantially reduced.

A further object is to provide a two-part closure as aforesaid which lends itself admirably to assembly by automatic machinery. I

Another object is to provide a-closure as aforesaid which may be expeditiously and reliably assembled with the receptacle by an automatic capping machine.

Other objects and advantages of the invention will become evident from the ensuing description which, taken with the accompanying drawings, discloses certain forms in which the principles of the invention may be embodied in practice.

IN THESE DRAWINGS FIG. la is a longitudinal. medial cross section of a closure in accordance withthe invention, together with a portion of the receptacle;

FIG. lb is a section similar to FIG. la but with the overcap partially engaged with the plug; 1

FIG. 1c is a section similar to FIG. Ia, but with the closure almost disengaged from the receptacle;

FIG. 2, 3 and 4 are sections similar to FIG. Ia, but showing modified embodiments;

FIG. 5 is a longitudinal, medial cross section of another embodiment including venting means;

FIG. 6 is a longitudinal, medial cross section of still another form;

FIG. 7 is a top plan view of the embodiment of FIG. 6;

FIG. 8 shows an alternate embodiment of the form of closure shown in FIG. 6; 7

FIG. 9 and 10 show other modifications; and

FIG. 11 is a cross section taken on the line Il-ll of FIG. 10.

SUMMARY or THE INVENTION Broadly regarded, the invention comprehends a closure for a receptacle whose contents, are to be dispensed by gravity discharged, such contents being liquid, powdered or of discrete size, e.g. capsules, tabletsor the like,and which may be injurious or fatal if ingested by a child, or even by an adult not exercising ordinary care. In one aspect the invention comprises a plug part of to obturate the discharge opening, e.g. the

Thus the manuare formed. The cap has a resilient top so constructed and dimensioned as to be depressiblc .by digitally-applied force. Onthe under side of this top there is an axial stem provided with a left-hand thread which is in axial alignment with a bore in the plug part, this bore being provided with a mating lefthand thread. When the top of the cap is in its normal, i.e. nondepressed state, the stem and bore are disengaged but, when the top is deformed inwardly and the cap is meanwhile rotated anticlockwise, as would be the case with a common overcap, the stem and bore are threadedly engaged. Continued rotation of the overcap exerts outward force on the plug until the overcap is completely unscrewed. The plug is then completely extracted from the neck or is still engaged to some minor degree permitting easy removal. If the pitch of the left-hand threads is made somewhat less than the pitch of the threads on the receptacle neck and mating skirt of the overcap. the stem will withdraw the plug from the neck concurrently with or prior to complete disengagement of the cap. Replacement of the plug and overcap is the reverse. Thus it will have become evident that opening of the receptacle involves two simultaneously ex erted actions: one, depression of the top of the overcap and two, rotation of the cap. It has been found that a child is unable to appreciate, much less perform, the two simultaneous actions. Similarly, in the case of the negligent adult or one whose discretion is impeded by age, mental impediment or a condition of semiwakefulness, lack of the necessary coordination will afford a suitable degerrent. In another aspect, where the receptacle is not provided with a threaded neck, but with a discharge opening defined by a short neck having an'exterior channel, the overcap is provided with a skirt having an inturned flange rotatably engaged with the channel. The

deformable top of the overcap carrying the stern having a lefthand thread and the plug having the correspondingly threaded bore, are as described above. It will be clear that, in any case, the positions of the stem and mating bore may be interchanged.

DESCRIPTION OF PREFERRED EMBODIMENTS Adverting to FIGS. Ia, 1b and 1c, there is shown a receptacle I0 provided with an exit opening II defined by an externally threaded neck I2. The threads 13 thereon are right hand, as will be understood, and may be of any conventional form, having a pitch of say three-sixteenths inches. The opening 11 is usually circular in cross section although the same may take other form. Serving to obturate the opening is a plug 16 of plastic composition, e.g. polyethylene, polypropylene or similar material having a resilient character in order that the part may have a moderate press fit in the opening. The degree of fit will be so calculated as to resist removal simply by using the fingers but to permit the plug to be withdrawn when the closure is manipulated in its intended manner. The lateral wall 17 of the plug 16 is shaped to conform to the opening; in the example, cylindrical. In the interest of good molding practice the wall 17 is thin, but not so thin as to render the plug easily removable by the fingers alone. To limit the degree to which the plug is thrust into the opening, the same is provided with a peripheral flange 21 adapted to abut the end of he the neck 12. Tofacilitate reinsertion of the plug following withdrawal the bottom wall 22 is desirably chamfered as at 23.

Wall 22 has a hollow boss 25 upstanding from its upper surface and the bore thereof has threads 27 which are left-hand, and of a pitch somewhat less than the pitch of the threads 13 for a reason to be explained. In the example, the threads 27 have a pitch of 18 threads per inch. It is within the scope of the invention that the threads 27 may be of multiple pitch and the threads 13 of single pitch, or both threads I3 and 27 may be of multiple pitch; further, one or both of the two sets of threads may be of the bayonet type.

An overcap 31 has a depending skirt 32 which is provided with threads 34 mating with the threads 13. On its exterior the skirt may be knurled or otherwise provided with an irregular surface to implement gripping, as is common. The top wall 36 of the cap is made depressable in response to an axially-applied force and may be flat, or crowned as shown. A hollow stud 37 depends from the top wall 36 and is coaxial with the boss 25. The stud is preferably hollow to comply with good molding practice. The exterior of the stud is provided with a left-hand thread 39 mating with the thread 27. In the disengaged condition of the parts some slight clearance will be allowed between the boss 25 and stud 37 in order that a slight deformation of the wall 36, such as a child may exert unknowingly is ineffective to cause engagement. At the corner whereat the top wall 36joins the skirt 32 a shoulder 41 is provided which, by abutting the flange 21. limits the extent to which the cap may be screwed on to the receptacle.

As mentioned above two different. concurrent actions are required to remove the closure: (1) downward force on the top wall 36 sufficient to present the stud 37 to the boss 25 while (2) rotating the overcap counterclockwise to cause partial engagement of the threads. FIG. lb illustrates the position of the parts at this point whereaftcr application of the downward force may be terminated but rotation of the cap continued. By providing multiple threads 27 and 39 initial engagement is facilitated. With a triple thread engagement can occur in l or less.

Continued rotation of the overcap will result in full engagement of the threads 27 and 39 (FIG. 10) so that the plug 16 will now rotate with the overcap and partake of its outward axial movement. The net effect is that the overcap and plug will be detached from the neck essentially simultaneously. By providing a pitch for the left-hand threads somewhat less than the pitch of the right-hand threads, it is assured that the boss and stud 39 are fully engaged prior to disengagement of the cap from the neck. It is also assured that the plug 16 is fully withdrawn from the neck of the receptacle before, or at substantially the same time as the overcap is free. Replacement of the closure is accomplished by screwing the overcap on to the neck 12 in a clockwise sense. As the overcap moves downwardly on the neck the plug will seize in the opening 11 so that continued rotation of the overcap will cause separation of the stud 37 and boss 25, the latter moving gradually downwardly into frictional engagement with the neck 12.

It may happen that, following withdrawal of the plug 16, the stud 37 will be found bottomed, and therefore jammed in the boss 25. To facilitate release of the jam a finger piece 9 may be provided. Thus, the overcap may be held in one hand and the plug unscrewed therefrom some slight amount to relieve the bound condition.

Alternatively a small, rounded protuberance may be located at the bottom of the boss 25. Thus, if the stud 37 is screwed in too far it will impinge on the limited area of the protuberance and jamming avoided.

To afford better grasp of the overcap while depressing the top wall 36 a flange may be provided. Accordingly the flange may rest on the index and third fingers while the thumb exerts the necessary axial force on the wall 36.

If desired portions of the top wall 36 may be removed, e.g. the stud 37 may be supported on the remainder of the overcap by a pair of radially disposed, deformable straps. Thus two open areas are defined through which the user may readily see whether the left-hand threads begin their engagement.

It will be understood that, since the diameter of the threads 13 and 34 is substantially greater than that of the left-hand threads 27 and 39, the substantial mechanical advantage thereby resulting greatly facilitates withdrawal of the plug 16.

FIG. 2 depicts an alternative form which differs from that of FIG. 1a in that the position of the parts 25 and 39 are interchanged. Operation is the same as heretofore described.

FIG. 3 shows another modification. In this case the plug 160 is the same as in FIG. 1a, and the top wall 36 of the overcap need not be deformable. e.g. the cap is of some nonresilient plastic, e.g. styrene. The post 390 has a stem 51 extending through a hole 52 in the top wall 36a. The stem 51 terminates in a head 55 supported on a pad 54 of resilient material, e.g. sponge rubber. Accordingly, to remove the closure the head 55 is digitally depressed concurrently with initial rotation of the cap to engage the left-hand threads, whereupon continued rotation is imparted to the cap, as previously described. This form of the invention has particular utility in those cases where the manufacturer is obligedto employ a cap of some material which must be inherently; rigid, e.g. one of sheet metal or rigid plastic composition The modification of FIG. 4 is thc same as in FIG. 3 except that the pad 54 is replaced by a bowed spring 57, having a hole or slot admitting the stem 51. I

FIG. 5 illustrates a closure having all of the characteristics of the embodiment of FIG. la except for the provision ofventing means. Many products. while confined. will generate gas at super-atmospheric pressure and. unless provision is made for venting, withdrawal of the plug of the closure could result in injury when the internal pressure is suddenly released. For example, certain formulations used in cleaning closet bowls contain sodium hydroxide, which is caustic, and uncontrolled spraying may injure the eyes. In the instant embodiment the plug 16b has an extension 61 which, being a continuation of the skirt 17a will be a reasonably tight, but sliding fit in the neck of the receptacle. The extension 61 has a peripheral bead 62 or equivalent projection to abut the shoulder 63 of the receptacle and thus prohibit complete withdrawal and consequent awkward reinsertion. However, the bead is made of such radial extent and transverse cross section as to be deformed upon initial assembly of the plug with the receptacle neck. The extension 61 has at least one part 66 extending from the bottom face of the part 16b to the bottom of the extension 61 in order to provide communication between the interior of the receptacle and atmosphere. Thus, when the plug part 1612 has been withdrawn to the position shown in phantom, accumulated gas is allowed to escape gradually through the port. It is to be noted that the plug and overcap are so related that the plug is withdrawn to venting position before the cap is completely detached. Consequently the vented gas will encounter the cap, whereby its rate of flow is decelcrated, and will issue past the threads 13 and 34 which, as will be understood, are not an airtight fit.

FIG. 6 and 7 illustrates a further embodiment wherein the deformable top wall 36 (FIG. 1a is replaced by a plurality of flexible straps 71, in this example, four, which extend upwardly and inwardly from the overcap 72. At the upper end the straps 71 merge into a hollow boss 75 which has an internal left-hand thread 76. The plug 77 is similar to the one described in connection with FIG. 1a, except that the upper portion 78 is dome-shaped with the stud 79 at its top. As will be apparent, this stud has a left-hand thread for engagement by the threads 76. To open the closure the boss 76 is depressed to engage the stud 79, the straps 71 meanwhile being deformed while concurrent counterclockwise rotation is imparted to the cap 72. Assuming that a child has unscrewed the cap 72 and the presence of the dome 78, the child is thwarted in an attempt to extract the plug 77 by pulling, since purchase with the fingers is impossible. Moreover, the stud 79, being very short, fails to afford a place of gripping. However, it is within contemplation to reverse the parts 75 and 79, in which case no protrusion. such as would otherwise be presented by the stud 79, is available. Insofar as concerns other details of the structure and function of the embodiment of FIGS. 6 and 7 the same are believed to be evident from the previous description.

The device of FIG. 8 is the same as in FIGS. 6 and 7 except that the straps 71 are replaced by an uninterrupted, substantially hemispherical, shelllike, deformable portion 81. Otherwise the description of FIGS. 6 and 7 applies.

FIGS. 10 and 11 relate to another alternative which includes venting means. As mentioned above it is possible for the contents of the receptacle to generate gas at super-atmospheric pressure. In this embodiment the bottom wall 85 of the hollow boss 86 is made sufficiently thin i.e. membranous so, as to be ruptured by the pressure within the receptacle, should the same reach a dangerous level. The top wall of the plug 16c carries a plurality of protuberances 87 defining with the overcap 31c a plurality of passages 86. In the event gas is released by rupture of the membrane 85 the same is vented through the passages 86 and thence through the usual clearance between the threads 13 and 34, to atmosphere. Otherwise the construction and function are as described above.

FIG. 9 is an example to illustrate one mode of incorporating a closure embodying the invention with receptacles adapted to receive a snap-on type of cap. In these cases the cap has a skirt 91 provided at itslower end with a peripheral bead 92. As is known, the cap. as an entirety, is so constructed as to be deformable when the same is removed or reattached. The mating portion of the receptacle; 93 comprises a channel 95 defined by an outwardly curled margin serving as the neck 96 of the receptacle. It will be understood that the interengaging cap and neck may both be deformable or only the cap may be so characterized. The head 92 desirably has a transverse cross section which is semicircular to facilitate snap-type engagement. The exterior of the skirt 90 may be knurled or otherwise formed as at 91, to improve the grip. If a child were to succeed in removing the cap. access to the contents is prevented by means of the plug 97 which is a comparatively tight fit in the neck 96 and which does not present; any feature by which the same may be withdrawn, even assuming that the child is stronger than the average. The plug 97 has a bore 98 having a left-hand thread and the top wall 99 of the cap carries a stud 101 which is threaded to engage the thread of the bore 98. The wall 99 is made sufficiently thin to permit the same to be deformed as was described with respect to H0, la. The function of this embodiment is believed to be apparent from the description given in connection withFlG. la, except that in this case the cap 90 simply rotates without undergoing axial movement. However, such rotation will withdraw the plug 97 from the neck 96, whereafter the cap and plug can' be removed jointly. The dimensions and proportions of the parts are so determined that when the stud 101 is bottomed in the recess 98 the plug 97 is either completely withdrawn or is so near withdrawal as to be easily removed upon detachment of the cap.

I claim:

1. ln combination, a receptacle and a closure for the same, said receptacle having a neck provided with an external righthand thread, said closure comprising'an overcap and a plug, said overcap including a skirt having an internal. right-hand thread engageable with said neck thread and a top surmounting said skirt, said top being of resilient, but generally shaperetaining material so dimensioned as to be depressible upon application of digital force axially applied thereto. said plug being adapted to be received within the neck with a snug, frictional fit, one of said top and plug having a male member within the overcap, and the other thereof having means defining a female counterpart of the male member and coaxial therewith, said member and aperture having respective lefthand threads mutually engageable upon depression of said top and rotation of said cap concurrently whereby such rotation withdraws the plug from the neck. I

2. The combination in accordance with claim 1 in which .adapted to bear on the flange when the overcap is screwed down on the neck.

6. The combination in accordance with claim 1 wherein said member and aperture are cylindrical, at least coextensively with the threads thereof. Y

7. The combination in accordance with claim I wherein said top is interrupted to define a plurality of ribs intermediate and joining said member or aperture-defining means, as the case may be, to the skirt to enhance the deformability of said top in response to the digitally-applied force.

8., The combination in accordance with claim 1 further characterized in that the outer end of said plug is convex outwardly to preclude digital grasping thereof.

9. The combination in accordance with claim 1 wherein said plug is provided with a passage providing communication between the interior of the receptacle and atmosphere when the plug is partially withdrawn from the neck for venting of gas generated within the receptacle during closed periods thereof.

10. The combination in accordance with claim 9 further characterized by means at the inner extremity of the plug to abut the inner end of the neck to preclude dislodgement of the plug from the receptacle.

11. The combination in accordance with claim 4 further characterized by means on said plug flange and means on the interior of the overcap together defining a passage between the interior of the receptacle and the adjacent surfaces of the engaged right-hand threads to vent the interior of the receptacle to atmosphere when the plug is withdrawn from the neck.

12. In combination, a receptacle and a closure for the same, said receptacle having an exit opening defined by a circular wall, said wall having an exterior, circumferentially extending channel. a plug frictionally received in said opening, an overcap overlying said plug and wall, said overcap having a lateral wall provided with an inwardly-directed flange received in said channel with a sliding fit to allow rotation of said overcap relative to said circular wall, one of said cap and plug having a stud provided with a left-hand exterior thread and the other thereof having means defining a bore coaxial with said stud, said bore having left-hand thread to mate with the stud thread, said overcap having a flexible top to support the stud or boredefining means as the case may be, said stud, in the unflexed condition of said top, being disengaged from the bore and,

- when said top is flexed inwardly by digitally-applied force and reverse, engagement 

1. In combination, a receptacle and a closure for the same, said receptacle having a neck provided with an external right-hand thread, said closure comprising an overcap and a plug, said overcap including a skirt having an internal, right-hand thread engageable with said neck thread and a top surmounting said skirt, said top being of resilient, but generally shape-retaining material so dimensioned as to be depressible upon application of digital force axially applied thereto, said plug being adapted to be received within the neck with a snug, frictional fit, one of said top and plug having a male member within the overcap, and the other thereof having means defining a female counterpart of the male member and coaxial therewith, said member and aperture having respective left-hand threads mutually engageable upon depression of said top and rotation of said cap concurrently whereby such rotation withdraws the plug from the neck.
 2. The combination in accordance with claim 1 in which said top wall is convex outwardly.
 3. The combination in accordance with claim 1 in which the pitch distance of the right-hand threads is a multiple of that of the left-hand threads.
 4. The combination in accordance with claim 1 further characterized in that the plug has a peripheral flange adapted to abut the outer end of the neck.
 5. The combination in accordance with claim 4 further characterized in that the overcap has an internal shoulder adapted to bear on the flange when the overcap is screwed down on the neck.
 6. The combination in accordance with claim 1 wherein said member and aperture are cylindrical, at least coextensively with the threads thereof.
 7. The combination in accordance with claim 1 wherein said top is interrupted to define a plurality of ribs intermediate and joining said member or aperture-defining means, as the case may be, to the skirt to enhance the deformability of said top in response to the digitally-applied force.
 8. The combination in accordance with claim 1 further characterized in that the outer end of said plug is convex outwardly to preclude digital grasping thereof.
 9. The combination in accordance with claim 1 wherein said plug is provided with a passage providing communication between the interior of the receptacle and atmosphere when the plug is partially withdrawn from the neck for venting of gas generated within the receptacle during closed periods thereof.
 10. The combination in accordance with claim 9 further characterized by means at the inner extremity of the plug to abut the inner end of the neck to preclude dislodgement of the plug from the receptacle.
 11. The combination in accordance with claim 4 further characterized by means on said plug flange and means on the interior of the overcap together defining a passage between the interior of the receptacle and the adjacent surfaces of the engaged right-hand threads to vent the interior of the receptacle to atmosphere when the plug is withdrawn from the neck.
 12. In combination, a receptacle and a closure for the same, said receptacle having an exit opening defined by a circular wall, said wall having an exterior, circumFerentially extending channel, a plug frictionally received in said opening, an overcap overlying said plug and wall, said overcap having a lateral wall provided with an inwardly-directed flange received in said channel with a sliding fit to allow rotation of said overcap relative to said circular wall, one of said cap and plug having a stud provided with a left-hand exterior thread and the other thereof having means defining a bore coaxial with said stud, said bore having left-hand thread to mate with the stud thread, said overcap having a flexible top to support the stud or bore-defining means as the case may be, said stud, in the unflexed condition of said top, being disengaged from the bore and, when said top is flexed inwardly by digitally-applied force and the cap rotated, said stud is engaged in the bore for withdrawal of the plug from said exit opening, said overcap flange and channel having a snap fit for disengagement of the cap together with the plug and similar, but reverse, engagement thereof. 